diff mbox series

[4.14,084/315] media: exynos4-is: Fix a use after free in isp_video_release

Message ID 20210719144945.641656061@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman July 19, 2021, 2:49 p.m. UTC 
From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>

[ Upstream commit 01fe904c9afd26e79c1f73aa0ca2e3d785e5e319 ]

In isp_video_release, file->private_data is freed via
_vb2_fop_release()->v4l2_fh_release(). But the freed
file->private_data is still used in v4l2_fh_is_singular_file()
->v4l2_fh_is_singular(file->private_data), which is a use
after free bug.

My patch uses a variable 'is_singular_file' to avoid the uaf.
v3: https://lore.kernel.org/patchwork/patch/1419058/

Fixes: 34947b8aebe3f ("[media] exynos4-is: Add the FIMC-IS ISP capture DMA driver")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/platform/exynos4-is/fimc-isp-video.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/drivers/media/platform/exynos4-is/fimc-isp-video.c b/drivers/media/platform/exynos4-is/fimc-isp-video.c
index 39340abefd14..c9ef74ee476a 100644
--- a/drivers/media/platform/exynos4-is/fimc-isp-video.c
+++ b/drivers/media/platform/exynos4-is/fimc-isp-video.c
@@ -308,17 +308,20 @@  static int isp_video_release(struct file *file)
 	struct fimc_is_video *ivc = &isp->video_capture;
 	struct media_entity *entity = &ivc->ve.vdev.entity;
 	struct media_device *mdev = entity->graph_obj.mdev;
+	bool is_singular_file;
 
 	mutex_lock(&isp->video_lock);
 
-	if (v4l2_fh_is_singular_file(file) && ivc->streaming) {
+	is_singular_file = v4l2_fh_is_singular_file(file);
+
+	if (is_singular_file && ivc->streaming) {
 		media_pipeline_stop(entity);
 		ivc->streaming = 0;
 	}
 
 	_vb2_fop_release(file, NULL);
 
-	if (v4l2_fh_is_singular_file(file)) {
+	if (is_singular_file) {
 		fimc_pipeline_call(&ivc->ve, close);
 
 		mutex_lock(&mdev->graph_mutex);